I think DR kind of recommends GALing and looking good and maybe that might lead the WAS to believe you may be moving on and not just waiting for them forever. Which I think is true for most of us.
I don't remember (could be wrong) DR recommending that you lie to your WAS. Besides the ethical problems with lying about something so serious, I think a lot of WAS might just feel less guilty about their A, and feel like the R is completely over and it's ok for them to do whatever. I personally couldn't do that, plus my kids would let my H know anyway, my d9 is esp. a huge talker!!! Karen